Category Archives: Panasonic GH5

Using Rectilinear Wide Lenses Underwater

I was checking the technical details of Alex Mustard Underwater Photography Master Class and the majority of wide angle pictures are taken with a fisheye lens. In the section about shooting sharks Alex says that he prefers to shoot sharks with a fisheye otherwise they look ‘skinny’.

If you look online on underwater video forums you frequently see comments on problems with wide angle lenses connected with the use of a rectilinear wide angle lens in a dome.

The two most common complaints are soft corners and distortion.

Soft corners are due to a combination of lens optical issues and dome port optics. In short any lens is to some extent curved and therefore if you shoot a flat surface the image may be sharp in the centre and softer as you move to the corners. Issues with field of curvature are corrected stopping down the lens. The issue with field of curvature happens everywhere not just underwater.

Right now there are four wide angle lens that can be housed for a micro four third camera:

Olympus 9-18mm

This lens has a nice working range that allows to capture 100 degrees diagonal at widest setting and still has a 35mm equivalent at the tele end. This is a pretty little lens at $699 is the most affordable option that can be put in a housing. You will need a wide angle port and the zoom gear. The whole combination for your Nauticam housing comes at $1,399. This lens can also be combined with a glass dome but this will make the whole combination much more expensive and you may want to think about getting a better lens instead.

Olympus 7-14mm

This is an outstanding lens especially on land due to the fast f/2.8 aperture. It is expensive at $1,299.99 and very heavy and bulky. The lens does not fit through the N85 port opening and requires a port adapter this gives the extra benefit of a focus know but with such a wide lens is not really useful due to high depth of field. You will need a 180mm glass dome and the zoom gear for the lens to complete the set up ending at a whopping $3159.99.

Panasonic 7-14mm

I have owned this lens and I have to say that at $799 is the right compromise between wide field of view and price. Furthermore once you get the zoom gear you have the option of a cost effective acrylic dome that will give you a very wide set up for $1589.99. There are reports of poor performance with this lens and it is true that is not as sharp in corners but the results are perfectly acceptable if you stop at f/8 in close shots.

Steering Wheel Truck
Panasonic 7-14mm with acrylic dome 9mm f/8
Exploring the Chrisoula
Panasonic 7-14mm with acrylic dome 7mm f/5

This lens is prone to reflections and flare however once you add the N120 port adapter and the 180mm glass dome this will get you to $2819 at that point you may want to consider the Olympus combination instead.

Panasonic Leica 8-18mm

This is my favourite lens is sharp does not suffer from field of curvature issues and has a very useful zoom range 16-35mm in 35mm equivalent. The zoom gear and the 7″ acrylic dome will take you to 1889.99 that is an excellent price point. The lens is not prone to reflection or flare and as the 7″ dome has a bigger curvature radius than the 180mm dome it will produce marginally better results.

Encircled
Panasonic 8-18mm in 7 acrylic dome f/8
Sunset Neat
Panasonic 8-18mm at 8mm f/10

The significant size of the acrylic port and the fact it floats make it ideal for split shots and this is the lens that gives me the best results.

This lens can also take port adapter that allows you to use the 180mm glass dome. This adds up to $2919.99 if you experience bad reflections and shoot frequently in the sun it may be worth it but I have not had any issue so far with this lens probably because of its nano coating.

I have found the 7mm focal length too problematic for dome ports and the amount of perspective distortion excessive generally it would be preferred to shoot at 9mm and narrower however this maybe insufficient for wreck interiors if you want a rectilinear look.

Perspective Distortion

One of the regular complaints of video shooters especially in wrecks or caves is that the edges look horrible and distorted and that there is an issue with the corners pulling. This is in fact not an issue but a problem with perspective as you shoot very wide angle. The following test shots will illustrate that the issue happens on land and has nothing to do with dome ports.

Shot at f/2.8 with Panasonic 8-18mm at 8mm shows sharp corners
Image with objects in edges at 8mm

As we can see the football looks like an oval and the chair is pulled. This is due to a perspective issue and is not a lens problem. When you shoot underwater video the objects on the edges of the frame change shape creating this pull effect that most people dislike.

Same scene at 9mm

At 9mm the amount of perspective distortion is reduced and this is the reason why 18mm on 35mm equivalent is one of the favourite focal length for rectilinear video and the maximum angle that should be used in small spaces to avoid the pulling edges.

One of the reason why a lens like the Nauticam WWL-1 is preferred for video is because the corners look sharp but is that really true?

Not really let’s apply some barrel distortion to simulate the WWL-1 to the image that looked badly distorted.

Barrel distortion applied -60 8mm

Now the football looks circular as we have applied -60 barrel distortion, obviously the rest of the image is now bent but this seems not to be of a concern to most people!

Barrel distortion -30 9mm

It needs much less correction to bring the 9mm shot into shape and for sure between the 8mm and 9mm the 9mm is the dimension that produces the most acceptable results.

It has to be said that in video with 16:9 aspect ratio most of the issue will be cropped away at the edges but the distortion in the middle of the frame will remain. For the same reason the 9mm image will appear practically rectilinear with no issues

16:9 crop still showing the edge ‘pulling’ at 8mm

16:9 crop looks straight at 9mm

I hope this post was useful there are four options for micro four thirds shooters to use rectilinear lenses I have settled for the Panasonic 8-18mm as in most cases it is still possible to control the perspective issue, I found this impossible at 7mm.

Bike on Hold 2
Bike in hold 2 on SS Thistlegorm Panasonic 8-18 at 8mm
Bubbling Bike
Shot at 7mm showing the front tyre pulling outside the frame

Obviously if you shoot in the blue this problem will not be visible however rectilinear lenses are popular with wreck shooters and I think this posts gives an idea of the challenges at play.

Finally I would discourage the use of the 7-8mm focal length range for video to those that want to have a rectilinear look.

From this post I started supporting Bluewater Photo in US for my links because it still provides multi brand and choice and because I learnt a lot from Scott Gietler Underwater photography guide back in the days where there was no internet resource to learn from.

The importance of Underwater white balance with the Panasonic gh5

One of the key steps in order to get the best underwater colours in your video is to perform a custom white balance.

This is true on land and on water because auto white balance only works in a specified range of color temperatures.

Panasonic GH5 advanced user manual

For our GH5 the range where auto works goes is approximately 3200-7500K. When the camera is working outside this range you get a colour cast. Let’s see with some examples:

Grey card Auto White Balance 8mm
Grey card Custom White Balance 8mm

In the example above I am taking a picture of a white balance reference card under warm lights that have a colour temperature of 2700K.

As you can see the auto white balance fails resulting in a yellowish tinge, while the shots taken after the custom white balance is accurate.

In terms of white balance card I use the Whibal G7 Studio 3.5″x6″ (8.9×15.2 cm). I found this card to work well underwater and I use it with a lanyard attached to a clip that I hook on my BCD D rings.

More info on the whibal here

It is possible to buy a larger card such as the reference that is 7.5″x10″ however this is cumbersome and I found the Studio version to work well with the Panasonic GH5 as it only uses the central part of the frame for white balance.

Custom white balance with the 8mm fisheye

Going back to our GH5 instruction manual you can also see that the camera white balance is limited to 10,000K which is the colour of blue sky.

Underwater due to light absorption at longer wavelengths red and orange disappear at depth and blue tends to scatter over suspended particles. So the colour temperature of water tends to be higher than 10,000K and also the blue is somewhat washed out by scattering.

This is the reason filters are essential because reduce the amount of blue or to say better cyan and bring the camera into a range where custom white balance works again.

I have already posted a whole range of observations on filters in a previous post so am not repeating here.

With the right filter for the water colour I dive in and with the appropriate white balance card you can get some pretty decent results with custom white balance.

To help the colour accuracy I have experimented with the Leeming Luts and I want to thank Paul Leeming for answering my obscure questions. Obviously you do not have to use the LUTs and you can design them yourself however I found that using the Cinelike D LUT I have a very good starting point for colour correction.

The starting point is a CineLike D profile with saturation, noise reduction and sharpness set to -5 all other settings to default as suggested by Paul, there is no need to lower the contrast as CineLike D is already a flat curve.

*Noise and sharpness have actually nothing to do with grading but are set to -5 as the GH5 applies sharpening and noise reduction even at -5 setting. Sharpening has generally a negative effect all around while noise reduction if required is better performed in the editor.

Looking at imaging resource tests of the GH5 we can appreciate that the camera colours are oversaturated by default.

the GH5 has around 113% over saturated colours

The GH5 tends to push deep colour and wash out cyan and yellow. This becomes apparent when we look at a white balanced clip uncorrected.

White balanced clip in final cut pro you can see how the water column is washed out whilst red and other dark colours are accurate

The Leeming Lut helps rebalancing the camera distorted colours and when you apply the camera LUT, provided you have followed the exposure instructions and applied the profile as described, the improvement is immediate.

The previous clip now with the CineLike D Leeming LUT applied

From here onwards it is possible to perform a better grading and work to improve the footage further.

For the whole read please look at Leeming Lut website

One other thing that I believe it is interesting is that while generally for ambient light or balanced light shots I do not actually trust the camera exposure and go -1/3 to -2/3 for close up shots exposing to the right greatly helps highlights recovery

In the two frames you can see the difference the LUT brings restoring the correct balance to the head of the turtle.

Turte detail the highlights appear blown out
Turtle detail with Leeming Lut applied

To be clear the turtle detail has been white balanced in water on the whibal card while using a Keldan Spectrum filter -2, then in fcpx automatic balancing is applied. The LUT brings out a better dynamic range from the same frames.

Obviously you are free to avoid lens filters and LUTs and to some extent it is possible to get similar results however the quality I obtain using automatic settings I believe is quite impressive.

I found myself most times correcting my own wrong exposures or wanting to increase contrast in scene where I had little however this only happens in sever circumstances where white balance and filters are at the limits.

Conclusion

There are many paths to get the right colours for your GH5 underwater videos in my opinion there are four essential ingredients to make your life easier and give your footage a jump start:

  • Take a custom white balance using a professional grade white balance card
  • Set the right picture profile and exposure when shooting
  • (Recommended) Use appropriate filters for the water conditions
  • Apply the appropriate LUT to eliminate the errors in the GH5 colour rendering in post processing

With the following settings producing a video like this is very simple and all your efforts are in the actual cutting of the clip.

Short clip that applies this blog tips

Please note some of the scenes that look off are shot beyond the working conditions of filters and white balance at around 25 meters…

which macro lens to pick for your gh5 or micro four third

I see many posts on line debating which macro lens is best for your micro four third system.

If I refer to the Nauticam system we have 4 macro lenses:

  • Olympus 30mm
  • Panasonic 30mm
  • Panasonic 45mm
  • Olympus 60mm

For the purpose of this article I will skip the Olympus 30mm as the Panasonic lens is known to be sharper and will focus on the other 3 lenses.

DxOMark is a popular tool for comparison as it gives you the results on one page. I have run it for the Oly 60 and the Pana 30 and 45 on the 20 Mpix OMD E-M1 MKII

DxOMark Comparison on Olympus OMD E-M1 MKII

Surprisingly the much more expensive Leica performs worse than the other cheaper models, this is confirmed on all internet sites running other type of tests.

What we can see is that there is little difference between the Panasonic 30mm and Olympus 60mm when it comes to image quality so whichever lens you choose your subject at the same level of magnification and aperture will have more or less the same detail.

Common Misconception: Shorter focal length give more depth of field

Many people think that using a longer lens is harder because there is less depth of field this is actually incorrect conceptually.

Let see why

Using an online calculatore like Dofmaster https://www.dofmaster.com/dofjs.html

Enter for the Panasonic GH5 the following parameters

Circle of confusion: 0.015 mm

Focal length 30mm

Distance 10.5 cm (minimum distance of the 30mm Macro)

Aperture f/11

Result Total depth of field 0.3cm

Now enter

Focal Length 60mm

Distance 21 cm (as it achieves the same magnification)

Aperture f/11

Result Total depth of field 0.3cm

So depth of field is not a consideration when choosing a macro lens…

Shooting a subject close to the background

In the following 3 shots am taking an image of a widget at f/11 at 29-44-60 mm on a Leica 12-60 (it is just easier it makes no difference to the outcomes)

Shot at 60mm
Shot at 44mm
Shot at 29mm

At the same aperture you can clearly see that there are no difference whatsoever in the detail and actually overall in the picture you don’t notice anything.

Shooting a subject far from the background

For the second shot I have moved the widget away from the wall.

Shot at 60mm
Shot at 44mm
Shot at 29mm

Again there is no difference in the level of detail of the widget however looking at the background we can see that

  • The 60mm shot reveals one brick and less than one quarter
  • The 44mm shot reveals one brick and a half
  • The 29mm shot reveals two bricks

So while the subject is exactly the same as the 60mm lens has a narrower field of view we see much less of the background.

This means that if you are shooting a nudibranch on the sand or something flat on a rock you won’t notice anything however if there is space behind the subject you will capture much more of that resulting in less subject isolation.

Underwater Comparison 30 vs 60 mm

In the first shot the Rhinopia is taken with a 60mm lens

Rhinopia Olympus 60mm

In the second shot the same Rhinopia with the 30mm (in a different place to be fair)

I have marked up with red the areas that with a longer focal length would have been minimised.

Which Lens to choose?

Now that we have clarified that depth of field is not a consideration and as each macro lens will have the same magnification there are only two factors that matter:

  1. Working distance
  2. Isolation from background

The 60 mm will have a longer working distance and at the same magnification will isolate the subject better from busy backgrounds, the 60 mm is also better for skittish subject because of the longer working distance. I have this lens and I have borrowed the 30mm in couple of occasions but do not have the 30mm yet.

There are however situations where longer working distance is not a benefit, specifically when the visibility is poor and there are suspended particles or the subject is really large.

In the example below I was at one meter from the two frogfish, a 30mm would have been better however the shot came OK.

Hairy frogfish Olympus 60mm

Conclusion

I believe the Olympus 60mm is a must lens to have. To date I have not felt the need for the Panasonic 30mm that is indeed a very sharp lens because I have always managed to pull out the shots. However for someone diving in murky water and focussing on nudibranches or subject laying flat on the seabed the Panasonic 30mm could be a better choice. I also want to say that using the 14-42mm at 42mm for me is actually a better choice for portraits and with a close up lens works very well with small subject not super macro and therefore as I already own the 14-42mm and various diopter for me the 30mm is not on the shopping list.

Getting the best colors in your underwater video with the panasonic gh5

There is no doubt that the Panasonic GH5 is a very capable camera and in given conditions the video performance you can get is truly impressive.

Broadly speaking a video clip needs to be:

  1. Sharp
  2. Colorful
  3. Contrasty
  4. Clean

Those 4 characteristics are tightly related to:

  1. Resolution
  2. Color depth
  3. Dynamic range
  4. Low Noise

Resolution

Today everyone shoots 4K and after all resolution is well supported by almost any camera, broadly is unaffected by other factors and unless the noise is really high sharpness of your frame is not going to be a real issue shooting at 4K.

Color depth

In normal conditions and not underwater a camera can resolve many colors. However underwater due to the diffraction of light and selective absorption of colours the starting point is very different from land. So generally is not the camera that cannot resolve the colors but the colors that are missing to start with. This post will focus specifically on this aspect. The Panasonic GH5 can resolve 23.8 bits in RAW and therefore technically has less than 8 bits color depth – do not confuse this with the 8 or 10 bit recording setting.

Dynamic Range

Underwater scenes tend to have limited dynamic range, with the exception of sunbursts or shooting against the light this is going to be an issue only in specific circumstances of very bright scenes with shadows. In all scenes taken with video lights dynamic range is not an issue at all. The GH5 has 13 stops of dynamic range but rarely this is an important consideration.

Noise

Noise is an important consideration as when the noise goes up the camera looses the other characteristics, color, dynamic range and resolution will be affected when the camera is outside the sweet spot. Broadly speaking the Panasonic GH5 does not do well once you pass the ISO 1600 setting and I tend to cap the ISO in video at 800 in most cases.

Diving Conditions

To understand how those variables play we can see how the same set up reacts very differently in scene where there is less light and therefore the camera uses high ISO like this one.

The same camera with exactly the same equipment in brighter water produces this

So the reason for the above is that with less light there are less colours and the clip looks what it is really.

OK moving on to the main subject of this post how do I get the colors right? It is a combination of techniques and the trick is to use the right one in the right conditions.

Generally every site has specific conditions that change depending on weather, time of the day, visibility and other factors. So in broad terms a site will have more or less light and therefore more or less colours. It is therefore impossible to categorically define what to do at a given depth but is more about typical values. With this in mind we have typically 3 scenarios:

  1. Ambient light shots
  2. Artificial light shots
  3. Balanced light shots

Close up Shots

In general close up shots especially of small subject fall within the scenario 2 for which a video light with high color rendering is important as this will define the colours you see. With a lot of power it is possible to extend artificial lighting to larger subjects but eventually you run out of power due to distance or size of the subject.

Wide angle shots and seascapes

True wide angle shots are generally ambient light shots which also means when it gets too dark the colors will be missing and it will look blue not matter the equipment.

In order to make the most of ambient light shots for wide angle it is essential to balance the colours in water even when you use a RAW format on a still image because RAW files are not as RAW as you think and are actually compressed.

Custom White Balance

Using Custom White balance with a grey card it is possible to obtain decent results until the camera hits the maximum color temperature in the case of the Panasonic GH5 this is 9900K. Depending on conditions you may get to 10-12 meters and this still works, in darker water this stops working much sooner.

Chrisoula K Bow
Chrisoula K Ambient Light 5 meters

Color Filters

Color filters push the limit of custom white balance further down. Some add more or less 4 meters others up to 6-8 meters at the expense of an overall loss of light. Filters are useful when there is a lot of light because also help to keep the Panasonic Gh5 in the best aperture range (not smaller than f/11)

Filter in action at 10 meters

Right now there are predominantly 3 filters on the market:

  1. UR PRO
  2. Magic filter
  3. Keldan Spectrum

All those filters will improve the performance and color rendering of your footage, under the conditions that the loss of light is not pushing the camera above reasonable ISO values.

In terms of depth range the magic filter and the Keldan Spectrum -2 version can be pushed to 15 meters depth on a bright day in clear water. The URPRO is capable of getting a few meters more down to around 17-18 meters although it does generate an orange cast (as there is no red left) it is still workable.

FilterLight LossTypical Max Depth
Magic Filter1 2/3 Ev15 meters
Keldan Spectrum -22 stop (WWL)12 meters
URPRO 1 2/3 Ev18 meters

This image gives an idea of the 3 filters as you can see they are very different one from the other.

Keldan top URPRO bottom Magic filter

Balanced Wide Angle Shots

This is an entirely new technique that has started with the Keldan Ambient light filters. I wrote a whole piece on wetpixel

The principle is to use custom white balance with or without filter to obtain color rendering and then put filters on the video light so that the color of the light emulates the ambient light and therefore it only gives texture not color.

Keldan has developed a whole range of filters for various situation that match their light and therefore are not applicable to any other light.

As I do not own a set of Keldan I have done some tests and found that a gel of Cyan filter 2 or 3 stops makes my divepro G18+ practically ambient light in the conditions I dive into.

FilterCyan Strength
Magic Filter2 stops
Keldan Spectrum1 1/2 stops
URPRO3 stops

The above value are based on my experience use at your own risk especially with different lights.

Square Cyan 2 stops Round Cyan 3 stops

To give an idea I overlapped the filter to my iPhone lens

This is the shot without any filters

Original Shot

URPRO and Cyan 3 stops (darker)
Magic filter and cyan 2 stops accurate
Keldan and cyan 2 stops accurate

This example shows that the two filters cancel themselves the result is almost daylight with no cast which means in water if you use a video light or a strobe you will not see a red or orange spots on the image.

For those taking pictures the same combination remains true with Inon Z240 and Sea and Sea YS-D2

Example picture here

five in a row
My own filter and Cyan 3 stop note that the light is coming from the other side

One thing to take into account is that you need to find a way to hold the gel on the video light or the strobes. The flat surface strobe diffusers make this process easy, finding something you can use with your video lights is not easy and also the gels may melt after continuous use.

Artificial lights

It comes a point and a depth where filters stop working, this could be as shallow as 8 meters in green water. As the scene is dark using lights is what is required. There is nothing specific about this technique except making sure you don’t get burned highlights or backscatter. As it happens in photography using long arms (maybe not as long as for stills) is key to get good lighting on your subject.

My Camera Settings

I use CineLike D with saturation, sharpness and noise reduction to -5. I shoot at 24/25p AVCI 400 mbps and follow the 180 rules, it is entirely possible to shoot at 1/100 if you like more crisp look.

Clearly there are people out there that do not like filters and think white balance is best etc but I think a good read on magic filters explains it all.

http://www.magic-filters.com/need.html

NAUTICAM WWL-1:THE BEST WIDE ANGLE LENS FOR UNDERWATER VIDEO (ON THE GH5 AND OTHER MICRO FOUR THIRDS)

It has been almost 4 years since my first review of the Nauticam WWL-1 wet wide angle lens and a few accessories later this lens is definitely my all time favourite for underwater video with my GH5.

I do not want to repeat myself and beat to death the topic of sharpness in corners I would rather recap on the other benefits of this lens that really make it unique for underwater video. Obviously this lens is very valid also for still images because of the ability to zoom through but this is not the focus of this post.

So let’s have a look at the three killer features of this lens that make it really special

Field of view

The WWL-1 once combined with the Panasonic 14-42mm MKII (the best lens to combine with the WWL-1 in my view) offers a field of view of 130 degrees diagonal. But what does that really mean?

First the WWL-1 does not compare with a rectilinear lens in fact it is almost a fisheye lens as we can see from those shots of a pool wall.

WWL-1 at 14mm wide end

The barrel distortion is evident correcting the image in lightroom gives an idea although not 100% correct of what is the real field of view of the lens.

WWl-1 at 14mm with distortion correction at 100

What is interesting to see is that the WWL-1 like a fisheye lens offers a much wider diagonal field of view than on the other dimensions.

I have compared the WWL-1 with other rectilinear lenses and with the 8mm fisheye.








Horizontal  25 50 100 200 FOV Linear Ratio to FE
7-14mm@7 62 124 248 496 102 57%
8-18mm@8 54 108 216 432 94 50%
12-60mm@12 36 72 144 288 72 33%
WWL-1 61 122 244 488 102 56%
Fisheye 8mm 109 218 436 872 130 100%







Vertical 25 50 100 200 FOV
7-14mm@7 46 92 184 368 86 84%
8-18mm@8 41 82 164 328 78 75%
12-60mm@12 27 54 108 216 57 49%
WWL-1 39 78 156 312 75 71%
Fisheye 8mm 55 110 220 440 96 100%







Diagonal 25 50 100 200 FOV
7-14mm@7 77 154 308 616 114 13%
8-18mm@8 68 136 272 544 107 12%
12-60mm@12 45 90 180 360 84 8%
WWL-1 107 214 428 856 130 18%
Fisheye 8mm 583 1166 2332 4664 170 100%

The table I have prepared uses the equisolid equation for a fisheye lens to map the WWL-1 I have verified the values and I can confirm the WWL-1 is somehow equivalent to 10.06mm fisheye lens.

There are two things that are worth noting, the first is that on the horizontal and vertical axis the WWL-1 is not wider than the Panasonic 7-14mm at 7mm. The other consideration is that with the WWL-1 the 4:3 format frame starts to become a classic 3:2 as the ration width/height is 1.56.

When we work in video at 16:9 we crop out most of the diagonal part leaving the rest of the field of view intact this means that in video mode the lens is much more rectilinear and the barrel distortion more contained.

14mm WWL-1 cropped at 16:9

If we look at a frame at 25mm we can see that at 4:3 the level of distortion is reduced but still present.

WWL-1@25mm

.The corrected frame shows the residual distortion.

WWL-1@25mm corrected
WWL-1@25mm 16:9 crop

The level of residual distortion in video mode is pretty negligible at 25mm. At 35mm even in 4:3 mode the WWL-1 is practically straight.

The benefit of the distortion of the WWL-1 is such that if you are shooting large sharks for example the barrel distortion makes those sharks look large in the centre of the frame and when they go out of the frame you don’t have the pull effect of a classic rectilinear lens behind a dome. At the same time if you need to shoot some divers or lines that are straight you can zoom in and still cover a pretty wide field of view.

Stabilization

The other benefit of the WWL-1 is that allows you to use lenses that are stabilised, today any lens at the 7-8mm range on micro four third has no stabilisation which means you need to use the in body stabiliser if available with your camera. For the GH5 this means that choosing a lens like the 14-42 MkII gives you access to Dual IS combining body and lens stabiliser and IS lock that really is useful when finning around. I just want to make sure that I am clear I am talking of this lens

https://www.panasonic.com/uk/consumer/cameras-camcorders/lumix-camera-lenses/lumix-g-lenses/h-fs1442ae.html

The Panasonic 14-42PZ power zoom is NOT compatible with dual IS so if you use this lens you either have in body or lens stabiliser not both. Obviously if you have a camera without stabilisation like the GH5s or the BMPCC 4K all of this is less relevant but still you can have some stabilisation instead of nothing.

I have not shot a comparative Dual IS vs Lens IS vs nothing in the pool but I am planning to do that soon. I can only say once you have dual IS with IS lock you don’t want to go back.

Filters

The final killer feature of the WWL-1 is that it gives you access to the Keldan Spectrum filters review here http://wetpixel.com/articles/review-keldan-spectrum-and-ambient-filters-by-massimo-franzese

Personally I think that any dive down to 18 meters in tropical or subtropical water will benefit from a filter but I also believe that conditions may change and in some cases you want to take the filter off. Now most of the rectilinear lenses for the GH5 do not even take a filter but also consider that once you fit one in dome port you are stuck with it for the dive. With the WWL-1 and the Keldan filter if you feel there is too little light and you want to get rid of the filter you can.

Keldan filter in action

DivePro G18 Plus video lights review

I managed to get hold of a pair of DivePro G18 Plus samples last week to use for my wide angle video hereby my thoughts on this product that I believe could be interesting for many video shooters.

Construction and technical data: solid anodised aluminium smoothly finished. Jaunt has decided to expose the battery that screws into the light head as oppose to house the battery itself into the light a more conventional design. The light features a Cree CXB3590 LED with a color temperature of 5000K and a CRI of 92 with declared output of 18,000 Lumens and a 95 degree beam angle. The battery delivers 14.4V with a total capacity of 6800 mAh giving an autonomy of 52 minutes at full power of 105 minutes at half power. The technical specifications of Creed LED give full details of the light used https://www.cree.com/led-components/media/documents/ds-CXB3590.pdf

When you look at page 14 performance group EB you see 15000 lumens nominal per bin, take into account that the array has an efficiency of 120% so this gives you the nominal lumens. In terms of viewing angle the nominal beam in air is 115 degrees and this in water gives you 100 degrees according to my calculations am not sure how Jaunt worked out 95 degrees. Looking at page 10 you can see that even at CRI=90 there is a spike in the navy blue colour this is most likely to show in water when combined with close up lenses as blue fringing and should be completely irrelevant at wide angle.

The provided chargers delivery only 1A with a declared charging time of 8 hours that frankly is totally unacceptable for a video light.

I recommend getting a spare battery the code is DivePro B06. The light has a color indication for the charge level around the switch button that is simple and effective at the same time although you don’t get your residual time in minutes as you do from some other products.

Ergonomics: the light feels very much like a torch and when attached to the included ball mount is very bottom heavy. The fresh water weight is 350 grams and becomes 370 grams with the mount. The light feels very well built, smooth and rugged.

Dry weight of the G18 Plus
Weight in fresh water

The light switch system allows for 100% 50% and any intensity from 1% to full power however this is slightly difficult to use, there is also an SOS feature. Generally the light feels well designed with few small niggles, the ball attachment is quite long this is not an issue except the light is already heavy on the bottom whilst the attachment to the arm is in the front part this creates a significant torque especially on land. Use of a bespoke underwater float is advised. Another minor issue of the ball mount is that it is not actually 1” but 2.65 cm. 1mm may seem little but it does bring the clamp off balance making it easier to loose grip. I recommend changing the o-rings with normal buna rings to reduce the size and improve grip if you use Ultralight, Inon or Nauticam arm systems. Another small issue of the switch system is that at rest on land the button may hit the floor. Previous version of the light switch on immediately at button press now Jaunt has changed the logic of the switch on to a long 2 second press to avoid accidentally switching on the light.

Video with the old switch mode

As the light overheats outside water this will prevent LED burnout. I had the latest version of the light, other copies on the market may still have the old logic check carefully yours.

Torch shape of the G16 Plus

Field test: Testing the light in a tank confirms the beam angle and the battery life as per specification more detailed testing is only possible in the pool.

I tested the lights in a pool with a 5 meters deep end. Pools have controlled conditions to check how the lights fall off and what is the real life coverage of the lights for your lens. It is not possible to provide a real test of the geometry of a light in the sea unless you know exactly the dimensions of what you are shooting and you have flat surfaces. I have some diving end of April in the Mediterranean will provide an update later on open water performance especially in terms of color rendering that I have not checked in the pool.

Beam angle: I took a series of stills at 80, 100, 150 from the axis of the lights using arms 28” long to which you need to add the length of the tray to determine where the light beams will meet.

As expected at 80 cm you see two separate circles of light, this become an elliptical shape at 100 cm and fill the frame at 125 cm with small fall off at the edges.

Dark Shadow as the lights are too close to the pool wall to merge the beams.

This pool shot gives an idea of the coverage only the edges are dark and the light is very nicely distributed. I have removed the reflections of the lights on the wall as they are distracting. 

1 Meter distance from the WWL-1 shot (1.15cm from light axis)

In order to understand the light falloff I ran the stills into a monitor equipped with false colour you can see the results here the lights are in my opinion very convincing and still deliver at 1.5 meters distance although you may need to pump up the ISO.

False colour shows good distribution of the beam across the frame. Note this is a 4:3 shot the 16:9 crop is the red frame

I would think that with this angle of coverage a distance of 30” between the two lights is ideal with my rig this means two 8” segments however this may create ergonomic issues so I settled at 5 + 8 this gives an arm length of 21” and with the GH5 26” from centre. Considering a WWL-1 set up with the front of the lens 6” ahead this means shooting distances up to 1 meters from the front of the lens covering a frame width of around 3.5×2.0 m that is a huge surface.

After the pool test I noticed a number of scratches in the paint clearly the coating is not the same quality of more expensive lights.

Conclusion

Overall the lights have great performance in terms of power, beam distribution and are very well built with excellent autonomy. Issues to note and suggested remediation:

  1. The chargers that come with the lights are inadequate. A 2A charger would be better and would halve the charge time without damaging the battery pack, here some links for  third party 16.8V/2A chargers:
    1. UK https://amzn.to/2YPyg4G
    2. US https://amzn.to/2HZEJoK
    3. Germany https://amzn.to/2I2hN83
  2. The clamp position creates an issue of pitch in water obviously if you manage to have some floatation system for the individual light this is no longer a problem.
  3. The light intensity adjustment is not effective and you can’t really tell if the two lights are set the same. Obviously this is only an issue if you need less than 9000 lumens for example for close shots. There is no easy solution to this problem other than controlling the two lights simultaneously.

Considering the price point and the quality this light competes with the Gates GT14 and the Keldan 8X and when it comes to power, CRI, autonomy and price beats them both in terms of durability and ergonomics they appear to be a level down but they are also less expensive.

Jaunt is setting up relationships with distributors in major markets and in UK there is already one so everybody should be able to get a set of lights. Depending on location, duties and import regulations the price will change but generally I have seen it remain competitive.

Macro video with the Panasonic gh5

Broadly speaking with the GH5 as well as with any other camera you have four categories of close up work:

  1. Close-up – frame size 10 cm or 4″ and wider typically hand held
  2. Super close-up – frame size 5cm or 2″ preferably on tripod
  3. Macro – frame size below 2″ only on tripod
  4. Super macro – frame size below 1″

For still images a typical choice is the Olympus 60mm, this lens however is very narrow so for any subject that is not too small and for the first category of close up you end up having working distances well above one foot. This in turns means more water to go through and makes it virtually impossible to cover larger subjects.

If you make that choice is because you have skittish subjects that do not like proximity and are very small. Furthermore the Olympus 60mm has not stabilisation and therefore with our GH5 will only use in-body stabilisation. Another side effect of using this lens is that it is impossible to take shots of divers or anything else at medium range so the videos end up being a collection of very close shots that may please someone but result fairly boring.

Of course you can make this kind of video exciting to an extent like here

But at the end for me something like this is more fun although of course the quality is very different (I shot this years ago with a Panasonic LX7 and edited in iMovie)

The difference between the stunning video of Dustin and the basic video of mine is that you only have very close shots in the first one and frankly a slideshow of still images would be equally nice. There is no description of any sort of where is the fish what are the conditions or anything at all. You may argue that the stuff to see is not that nice but at the end this gives you a real idea of the diving where you go which is the purpose of my videos and majority of non Pro people. Furthermore medium size subjects that move like octopus, squids, crabs will almost always exhibit some kind of behaviour.

My macro video rig is built around the Panasonic 14-42 MKII which is the same lens I use for wide angle video with the Nauticam WWL-1. In effect am running video like a compact set up.

GH5 Macro Video Rig as at 29 March 2019

Ergonomics and lens

  1. The field of view with at 42mm is only 23 degrees horizontal and 13 degrees height this is ideal for portrait type of work
  2. I still use my old Sola 1200 video lights that can be used with a 20 degree beam creating a snoot like effect to better isolate your subject. It can be argued that color rendering index of newer lights is better but I think the narrow coverage of the lights is more important. Consider that at wide end the field of view is less than 60 degrees anyway with the flat port at 18mm
  3. I use two close-up lenses with a Saga dual flip diopter
  4. The rig as described is heavy in water more than 700 grams negative to ensure the required stability
  5. The tripod base has 2x 3″ segments and 1x 5″ segment to be as close as possible to the bottom this creates issue if you do not have a monitor as you need to have your face in the sand however once the shot is framed all is good

Close-up lenses

I use two close up lenses with this rig as the 14-42mm as a working distance in water around 26cm and a minimum frame size around 9cm that is pretty wide.

SubSee 5 wet lens

The SubSee 5 is in the sweet spot for the 14-42mm lens because it starts working pretty much when the 14-42mm can-t focus anymore and down to around 10-12 cm working distance. Minimum frame size is 46 mm

SubSee 5 + 14-42@42mm

Using the Ex-Tele feature in video means we can get to 33mm which is below the 36mm classic DSLR 1:1

When this is insufficient and the subjects are really tiny the next lens is the Nauticam CMC-2

Nauticam CMC-2 on Saga dual flip holder

The CMC-2 gives a frame size of 32mm as in this image

Panasonic 14-42@42mm with CMC-2

Using Ex-tele this becomes 23mm which is the same you get with the CMC-1 without ex-tele and is plenty for any purpose. It is theoretically possible to stack the two close up lenses but is not really necessary and the working distance too small. The CMC-2 works around 6-7 cm so you have still space for lights etc.

Olympus 60mm

Is there any use for this lens? Of course there is in case you want to capture a frame smaller than 23mm with the 60mm you can get down to 17mm with the bare lens to 12mm with the Ex tele, 9 mm with the CMC-1 and 6 mm with CMC-1 and ex tele. Will you be able to focus and work with the CMC-2 at 22mm from the subject is another discussion however for skittish subjects it gives you more working distance and this may be needed. I would recommend taking this lens with you for those cases but for video I do not see how you can really use the CMC-1. Please note the CMC-2 is useless with the 60mm as the working distance improvement is minimal to none.

Panasonic GH5 Demystifying Movie recording settings

 

There are a lot of videos on YouTube that suggest that there is not much difference among the various recording settings of the GH5 for UHD.

To recap we have 4 settings for UHD (I will refer to PAL system because it is easier but all applies equally to 24p, the 30p/60p format will be the same with worse results)

  1. 100 Mbps 420 8 Bits Long GOP 25p
  2. 150 Mbps 420 8 Bits Long GOP 50p
  3. 150 Mbps 422 10 Bits Long GOP 25p
  4. 400 Mbps 422 10 Bits All-Intra 25p

The difference between Long GOP and All Intra is that in the Long GOP what is encoded is a group of pictures (GOP) and not separate individual pictures. In this article I will use ProRes as a proxy to AVC-Intra as, in the GH5 implementation, they have very similar logic and performance you can find some posts on the internet of people trying to discern the two but there really is not difference as essentially this is just image compression. 

Within a Group of Pictures there are different type of frames:

  • I (Intra coded) frames containing a full picture
  • P (Predictive coded) frames containing  motion interpolated picture based on a prediction from previous frames
  • B (bi-predictive coded) frames containing a prediction from previous or future frames

It is important to note that frames are not stored sequentially in a GOP and therefore the GOP needs to be decoded and the frames reordered to be played, this requires processing power.

The reason why H264 is very efficient is that within a group of picture there is only one full frame and the rest are predictions clearly if the prediction algorithm is accurate the level of perceived quality of long GOP is very high and similar to All-Intra clips.

This is the reason why comparing All Intra and Long Gop using static scenes or scenes with repetitive movement that can be predicted very accurately by the codec is a fundamental error.

Incorrect example here:

The scene is composed of static predictable objects with no motion and after YouTube compression the (wrong) conclusion is that there is no absolute difference between the codecs. Instead what this shows is the effectiveness of Long GOP when the prediction is accurate which is exactly the point of the codec plus the fact that YouTube flattens differences due to heavy compression and use of Long GOP.

Another example is a bit better as it uses a fountain which is a good representation of unpredictable motion

In the 300% crop you can see how All_Intra performs better than Long GOP in terms of prediction despite the YouTube compression, but generally those tests are unreliable if you see the last section of the video where there is a semi-static scene you cannot really take the three examples apart.

So why is that and is there any point selecting different settings on your Panasonic GH5?

In order to understand the workings we need to dig deeper into the structure of the GOP but before doing so let’s evaluate the All-Intra codec.

AVC All-Intra explanation

This codec records at 400 Mbps so with 25 fps this means circa 16 Mbits per frame or  1.9 MB per frame and there is no motion interpolation so each frame is independent from the others. The implementation of All-Intra of the GH5 does not make use of CABAC entropy encoding as Panasonic does not believe this is beneficial at higher bit-rates making this AVC-Intra implementation very close to ProRes as both are based on Discrete Cosine Transform.

If you consider a Jpeg image of your 3840×2160 frame on the GH5 you see that it stores around 4.8 MB per image because there is no chroma sub-sampling so if you wanted to have exactly the same result you would need to use ProRes 4444 to get a comparable quality (this not even taking into account that Jpeg are 8 bits images).

Video uses chroma sub-sampling so only part of the frame contain colours at a given time. Apple in their ProRes white paper declare that both ProRes 422 and 422 HQ are adequate to process 10 bit colour depth and 422 sub-sampling however they show some quality differences and different headroom for editing. If you count 50% for 4.2:0 sub-sampling and 67% for 422 you get around 2.34 MB and 3.5 MB frame sizes that correspond to ProRes 422 and ProRes 422 HQ individual frame sizes.

In simple terms All Intra 400 Mbps would fall short of Apple recommended bit-rate for 422 10 bit colour for circa 92 Mbps is like saying you are missing 0.44 MB from your ProRes 422 frame and 1.6 MB from ProRes 422 HQ and you have 0.3 MB more than ProRes LT however I do not have the full technical details of ProRes to evaluate directly.

The real benefit of such codec is that it can be processed with modest hardware without conversion as the AVC Intra codec is edit ready and each frame is captured individually without any motion artefacts and therefore the computer does not have to do a great deal of work to decode and render the clips.

In order to record All-Intra in your memory card you need a V60 or higher specs card which in terms of $ per GB costs you more than an SSD drive however you no longer need a recorder.

Coming back to the other recording quality option we still need to evaluate how the various long GOP codecs compare relative to each other.

In order to fully understand a codec we need to decompose the GOP into the individual frames and evaluate the information recorded. If you look on Wikipedia it will tell you that P frames are approximately half the size of an I frame and B frame are 25%. I have analysed the Panasonic GH5 clips using ffprobe a component of ffmpeg that tells you what is exactly in each frame to see if this explains some of the people claims that there is no difference between the settings.

Link to Panasonic documentation

 

100 Mbps 420 8 Bits Long Gop 25p Deep Dive

An analysis with ffprobe shows a GOP structure with N=12 and M=3 where N is the length in frames of the group of pictures and M is the distance between I or P frames.

So each Group of Picture is made like this

IBBPBBPBBPBBP before it repeats again.

A size analysis shows that B frames are in average 14% of the I frame and P frames are around 44% of the I frame.

I B B P B B P B B P B B
Size 1648326 247334 237891 728777 231947 228048 721242 228347 227544 713771 236866 232148
Ratio to I frame 100% 15.01% 14.43% 44.21% 14.07% 13.84% 43.76% 13.85% 13.80% 43.30% 14.37% 14.08%

With an average video bit-rate of 94 Mbps each GOP has 45.3 Mbps which means an I Frame has around 13.1 Mbits or 1.57 MB per frame and an equivalent All-Intra bit-rate of approximately 328 Mbps however this codec is using CABAC entropy encoding that Panasonic states is 20-30% more efficient than CAVLC used in All-Intra so net of motion artefacts this codec is pretty strong.

150 Mbps 420 8 Bits Long GOP 50p Deep Dive

An analysis with ffprobe shows a GOP structure with N=24 and M=3 where N is the length in frames of the group of pictures and M is the distance between I or P frames.

So each Group of Pictures is made like this

IBBPBBPBBPBBPBBPBBPBBPBB before it repeats again.

A size analysis shows that B frames are in average 13.4% of the I frame and P frames are around 41% of the I frame. With an average bit-rate of 142.7 Mbps each GOP has 68.5 Mbits which means an I Frame has around 11.3 Mbits or 1.35 MB per frame and an equivalent all Intra bit-rate of approximately 566 Mbps. Again this uses CABAC entropy encoding so the equivalent All-Intra is higher.

One very important aspect of the 150 Mbps codec is that as the GOP is double the length of the single frame rate 100 Mbps codec there are the same number of key frames per second and therefore it is NOT true that this codec is better at predicting motion. In fact it is exactly the same so if you had acquired a 100 Mbps codec at 25 fps and then slowed down the footage to half speed asking your editor to interpolate intermediate frames it would come to the same result although with some more processing required.

150Mbps 422 10 Bits Long Gop 25 fps

An analysis with ffprobe shows a GOP structure with N=12 and M=1 which means this codec does not use B frames but just I and P frames so the GOP structure is as follows:

IPPPPPPPPPPP before it repeats again.

A size analysis shows that P frames are on average 53% of I frames so this codec is in fact less compressed however this has also some consequences.

With an average bitrate of 150 Mbps each GOP has 72 Mbits which means an I Frame has around 10.5 Mbits or 1.25 MB per frame and an equivalent all Intra bitrate of approximately 262 Mbps. So this codec in terms of compression efficiency this is actually the worst and this is due to the lack of B frames.

We can only think that the Panasonic GH5 processing is not strong enough to capture 10 bit and then write 422 Long GOP with IPB structure.

Codec Ranking for Static Image Quality UHD

So in terms of absolute image quality and not taking into account other factors the Panasonic GH5 Movie recording settings ranked by codec quality are as follows:

  1. 400 Mbps 422 10 Bit All intra 25 fps (1.9 MB per frame)
  2. 100 Mbps 420 8 Bit Long Gop 25 fps (1.57 MB per frame)
  3. 150 Mbps 420 8 Bit Long Gop 50 fps (1.35 MB per frame)
  4. 150 Mbps 422 10 Bit Long Gop 25 fps (1.25 MB per frame)

The 100 Mbps  and 400 Mbps codec are marginally different (21% larger frame size) with the 422 10 Bits long GOP really far away.

Conclusion

If you want to record your footage to the internal memory card you are really left with two choices:

  1. Use the 100 Mbps Long Gop codec it is very efficient in the compression and the perceived quality is very good. It does however require you to convert to ProRes or similar during editing if you don’t want to overload your computer as the codec is really heavy on H264 features. You need to get the exposure and white balance right in camera as the clips may not withstand extensive corrections. There is a risk with footage with a lot of motion of some errors in motion interpolation that can generate artefacts.
  2. Buy a V60 or V90 memory card and use 400 All intra at single frame rate. This will give you edit ready footage of higher quality without motion artefacts, You still need to get exposure and white balance right in camera as the headroom is not so large to allow extensive corrections. The bit-rate and frame size is not sufficient to really give you all the benefits of 422 sampling and 10 bit colour but it will be a good stepping stone to produce good quality rec709 420 8 bit footage.

Generally there appears to be no benefit using the internal 422 10 Bit codec nor the 420 8 bit double frame rate due to the limitations of the GOP structure, here Panasonic has created a few options that to be honest appear more a marketing effort than anything else.

There may be some use to the 150 Mbps double frame rate if you intend to slow down the footage after the conversion to ProRes or similar but the extremely long GOP does not make this codec particularly robust to scenes with a lot of motion and in any case not more robust than the 100 Mbps codec.

A final thought if you are interested in 10 bit colour is that the FHD All Intra 200 Mbps codec has enough quality and headroom to allow manipulation. This is in fact the only codec that has bit-rate higher than ProRes HQ at least at 24 and 25 fps so if you want to check the real range of colours and dynamic range the camera is capable of you should try this codec.

Note: I have removed some comments on ProRes and external recorders as there are plenty of people that believe that the intra codec does better than ProRes HQ on the Atomos

Panasonic GH5 settings for underwater video

In the previous post I described the HDR settings especially relevant if you have an external recorder. However there is quite a lot of discussion if it is worth shooting HDR underwater video with the Panasonic GH5 at all. This follows the discussions about using VLOG L underwater versus studio production: many people that start using VLOG L revert to a more normal setting something using standard profiles and not even Cine profiles because the workflow is just too much work.

In general there are 3 characteristics that are important to underwater footage but more in general to any footage: colour , contrast and noise. This is the reason why when you look at DXOMark you have some measures of those 3 characteristics.

GH5DXOMARKSCORES

What DxOMark is telling us is that looking at a RAW image produced from the GH5 the colour depth is at best 23.9 bits, the dynamic range is at best 13 Evs and the Low-light ISO that still gives some decent colour depth and dynamic range is 807 ISO.

Let’s have some interpretation of those measures colour depth of 23.9 bits means 15.6 millions colours, this is actually less than true colour of an sRGB display. Considering the RGB scale the 23.9 bits per colour really mean 8 bit colour. OK so why does the camera have a 10 bit colour (equivalent to 30 bits per pixel no camera reaches that even full frame) option at all? We will talk about it in a minute…

Dynamic range for a RAW image is 13 Evs however Panasonic says VLOG L offers 12 stops compared to 10 stops of professional SDR footage. Now 12 stops require a display with a contrast ratio of 4000:1 which is beyond all commercial computer monitor and in the range of HDR devices. The new VESA DisplayHDR standard HDR600 is a minimum requirement to display this level of contrast ratio.

Finally the Low-light ISO of 807 (corresponding to 1600 on your GH5 as ISO values are always incorrect and geared towards higher values for marketing reasons) means that unless you are at the surface pretty soon there won’t be any colour or dynamic range to show (low-light ISO requires 18 bit colour depth 9 Ev Dynamic range and 30 dB SNR).

WHAT ABOUT THE GH5S?

The GH5s will give you 1.5 stops more of low-light performance and therefore your footage will look good until ISO 2400 or ISO 4800 looking at the camera settings which is quite a bump.

OK now coming to the main point of the post having seen those limitations why would I bother shooting in VLOG or HLOG?

First consideration: Noise

As we have seen both dynamic range and colour depth drop considerably when ISO goes up. In short unless you have abundance of natural light or you are shooting macro with a lot of artificial light is unlikely you will see any benefit shooting VLOG or HLG.

Considering that compression brings additional noise here we see why shooting with an external recorder at higher bitrate really helps fighting noise even if you don’t shoot log because you reduce the compression artifacts. If you don’t have a recorder consider setting a max ISO limit quite low around 1600 on your GH5 or you will see a lot of grain.

Second consideration: color depth

If the camera cannot even resolve 10 bits per pixel RGB why would you shoot 10 bits? When you shoot VLOG or HLG you are not operating in the REC709 colour space which is limited to 8 bits so it is possible that the colour that the sensor is capturing are not all the 16.7 millions of the RGB palette but some of them are outside in the Dci-P3 or even REC.2020 colour space. Clearly if you do not have a 10 bit screen (and almost all computer screens are 8 bits) or 8 bits with FRC to simulate 10 bits, this is a total waste of time and you won’t see those colours and nobody on a computer working in sRGB will see them either. So unless you have a proper screen to watch your clips there is no point working in 10 bits. When it comes to grading again if you can’t display those colours it won’t be possible to do your work properly so don’t waste your time and shoot in 8 bits.

You now understand why you can’t see any difference in all those youtube comparison that by the way have been encoded 8 bits!

A lot of people records in VLOG 10 bit to then produce in REC709 that has 8 bit colour and the reason is that they have proper grading monitors to see what they are doing.

Just to give you an example laptops with exception of some recent MacBook Pro and others like the Dell XPS can’t display 10 bit colour. An iMac displays 10 bit colour and some screens that support DCI-P3 also are capable any other RGB screen won’t work.

Conclusion don’t waste your time with 10 bit if you don’t have a decent screen and if you only produce for youtube.

Third consideration: Dynamic range

VLOG and HLG start at base ISO 400 (that really is 200) and this is where you have your 12 stops. Once you get to ISO 1600 (nominal 3200 on your GH5) you still have 9.5 stops but the colours are gone. Generally it does make sense to shoot LOG however the issue may well be that your editing display is not HDR600 and therefore you can’t really see what you are shooting accurately. Having a screen that can correctly display HDR is even harder than finding one that can display 10 bit colours. What you need to consider though that unless you are capturing a sunburst or a backlit scene or you are shooting the surface you will not have more than 10 stops in your scene anyway.

Conclusion

The settings you can shoot really depend on your editing and display devices.

If you have a laptop or just an 8 bit computer screen and no external recorder you can shoot at 100 mbps 8 bit colour with the picture profile of your choice, standard, natural, cine like whatever you like as you won’t be able to tell the difference at any point in the process from any other formats 10 bits logs etc.

If you have a DCI-P3 display or better for editing shoot 10 bit colour. Examples are iMac and MacBook Pro or some Philips or Acer screens on the market.

If you have an HDR display for editing and an HDR Tv set shoot HLG.

If you have an external recorder shoot in PRORES HQ (as the GH5 does not support camera RAW). Some of those recorders like the Atomos Shogun Inferno support HDR and can also be used for editing with some adapters so shoot in HLG to get the best results.

Generally VLOG L requires a lot of work and is best suited to studio production so if you don’t have a good grading set up don’t waste your time with it.

If you are one of those shooters that after a lot of trial and error ended up shooting 8 bits colour because you don’t have a recorder or shooting natural or cine-like because you don’t have a proper grading HDR monitor now you know why you are doing what you are doing….

Setting up your GH5 for HLG HDR capture

We got our GH5 ready for HDR capture in the previous post so how do we make the most of it?

If you have an external recorder or monitor that supports HDR it is easy! Also if you do you probably have a fair bit of money and you are not reading this blog…

Currently Atomos recorders that can be housed all support HDR including HLG

DSC_9783_2c838594-1601-42d1-b145-40821cd34bb2_1024x1024
Nauticam Atomos Flame

The Nauticam Atomos Flame available at list price of $3,650 will house the Shogun Inferno, Shogun Flame, Ninja Inferno and Ninja Flame

On the Atomos website you can see that for the GH5 the products recommended are the Ninja and Shogun Inferno there first is priced at $995 and the second at $1,295.

There is a difference of $300 between the Shogun  and the Ninja  however the Shogun  provides an SDI video port that may turn out quite useful in grading phase. So if you got to the point of spending $3,650 for the housing I would definitely invest the extra $300 needed for the Shogun Inferno.

Once you get a recorder you can set up the GH5 to output 4Kp50/60 at 10 bit and be happy. The HDR screen of the Atomos device will provide the real time monitoring you need to expose footage properly in HLG. It is not my intention to start a debate about log vs HLG there is plenty of material out there.

A very good video is here

If you don’t have a recorder you are left to the GH5 screen that does not support HDR so how are you going to expose correctly? You have a couple of tools available.

The first one is Zebra Patterns that can be accessed in the Monitor subsection of the menu.

There is a great tutorial on YouTube

Now if you are working in HLG you will notice that the maximum value that can be set is 95% this is because luminance in HLG is limited to 64-940.

If you look on ITU website you can see that white ranges between 69 and 87 in HLG so using Zebra we can still attempt at exposing properly without an HDR monitor.

If you do have a reference white balance card you should set the Zebra to 75% as this is the reference for white if you are in the field without a reference your value should be set to max 90% to ensure you don’t blow highlights. Now you will find some website that tell you 95% is fine too but you do want to leave a bit of headroom. If you want you can set Zebra 1 to 75% and Zebra 2 to 95% so you cover all eventualities.

So once you have set the Zebra the next step is to decide if you want to use HLG View Assist or not. Here you have three options:

  1. Off
  2. Mode 1
  3. Mode 2

Off leaves the display in REC709

Mode 1 gives priority to background areas for example the sky

Mode 2 gives priority to the main subject

The 3 modes are really a progression of brightness, when Off the image looks completely desaturated and Log like. In Mode 1 the image appears to have a preference to show shadows in Mode 2 the image looks the brighter and the most punchy making it easy to work on the foreground but crashes the black and shadows quite a bit.

No matter what you select the Zebra value remain unchanged.

The final setting that can be useful is the Waveform monitor which is accessible in the creative video menu. As the Zebra this gives you a real time display of the image within a diagram that on the horizontal axis represent the image left to right and on the vertical has the signal. This is practically a spacial representation of your image and has the same intensity of the Zebra from 0 to 100. So anything too dark on the bottom won’t be visible and things above max will be clipped.

There are several tutorials available on YouTube

So in essence you could try to expose correctly using Zebra and waveform monitors on the GH5 LCD display but let’s face it the screen is tiny and underwater you won’t be really able to use it effectively. If you have an external monitor or recorder this becomes more useful and something to effectively try.

If you are using the camera meter to expose remember that the GH5 as most cameras has only three settings for metering: multi area, center weighted and spot those influence how the camera calculates the average exposure, this is true also if you use manual mode the reading on the meter will change depending on the metering mode. However for what we have said here if your objective is simply not to clip highlights you have a long way to go before reaching 90% IRE with HLG.

In short you have three options to set exposure on your GH5:

1. Super lazy option trust your camera meter as this was a still image, most likely you will be exposing to the right and without further checks there is a chance to have dark area or clipped highlights.

2. Use Zebra and manual exposure in combination with the camera meter to ensure you stay within safe limits.

3. Use waveform monitor and completely ignore the other parameters as this gives you full control of what you are shooting and removes any dependency on having or not an HDR monitor

As a final note it is important to remember that performing a white balance adjustment is essential in order to expose correctly it is not just to get the colour right as the IRE values on what is white actually change and the camera makes assumptions on what is white to calculate the rest. This is especially true for environment in difficult light conditions.

Getting yourself familiar with waveform monitoring is essential for editing as majority of people will not have the possibility to grade on an HDR screen. In the next post I will explain how to get the lowest possible cost HDR screen that supports HLG.